North Korea fired a ballistic missile from a submarine on Saturday but it appears to have failed soon after launch, South Korea’s military said.

Point of view

The launch comes at the end of a week of sharply rising tensions on the peninsula. It is only a day after the U.S. and South Korea pledged to deploy an advanced anti-missile system to counter threats from Pyongyang, and two days after North Korea warned it was planning its toughest response to what it deemed a “declaration of war” by the United States.

That followed Washington’s blacklisting of the isolated state’s leader Kim Jong-un for alleged human rights abuses.

The South’s Office of the Joint Chiefs of Staff said in a statement that the missile was launched at about 0230 GMT in waters east of the Korean peninsula.

The missile was likely fired from a submarine as planned but appears to have failed in the early stage of flight, the Joint Chiefs said.

South Korea’s Yonhap news agency said the missile’s engine successfully ignited but the projectile soon exploded in mid-air at a height of about 10 km (6 miles), and covered not more than a few kilometres across the water.

The South’s military declined to confirm those details.

The missile was detected in the sea southeast of the North Korean city of Sinpo, South Korea’s military said. Satellite images indicate Pyongyang is actively trying to develop its submarine-launched ballistic missile programme in this area, according to experts.

Neighboring Japan, the United States, and South Korea’s military condemned the missile launch as a flagrant violation of U.N. sanctions.

The missile launch is a “clear challenge to U.N. Security Council resolutions,” Japanese Prime Minister Shinzo Abe said on Saturday, according to Kyodo news agency.

The U.S. said it was monitoring and assessing the situation in close coordination with its regional allies and partners.

“We strongly condemn North Korea’s missile test in violation of UN Security Council Resolutions, which explicitly prohibit North Korea’s use of ballistic missile technology,” said Gabrielle Price, spokeswoman for the Bureau of East Asian and Pacific Affairs at the U.S. Department of State.

“These actions, and North Korea’s continued pursuit of ballistic missile and nuclear weapons capabilities, pose a significant threat to the United States, our allies, and to the stability of the greater Asia-Pacific,” she added.